Question: Some cars were parked in the toy store parking lot. 3 more cars park at the toy store. Now there are 78 cars in the parking lot. How many cars were parked at the toy store at the beginning?
Solution: The number of cars parked at the store at the beginning is the difference of the number parked now and the number that came and parked earlier. The difference is $78 - 3$ cars. $78 - 3 = 75$ cars.